1. Field of the Invention
The present invention relates to novel phenylalkyl sulfamate compounds, a muscle relaxation and a method for preventing or treating a disease associated with muscle spasm.
2. Description of the Related Art
Myotony or spasm is frequently observed as a sequel of head injuries, and is difficult to treat.
Myotony is one of skeletal muscle dysfunctions resulting from muscle tone increase, and is caused by central nervous system damage due to wound and various other causes. The causes of muscle tone are abnormal posture, fatigue, degenerative change in spine, etc. And, Myotony can be induced by one of various causes including skeletal muscle spasticity and spastic paralysis causing serious hindrance to daily life. Particularly, spastic paralysis involves symptoms such as tension of the hand and feet, stiffness, difficulty when walking, etc., and causes serious hindrance to daily life. Centrally acting muscle relaxants block receptors related to the excitement of skeletal muscle function, or excite receptors related to the inhibition of skeletal muscle function, in order to relax muscle tone or decrease excessively activated reflection function thus causing muscle relaxation. The centrally acting muscle relaxants may include methocarbaamol, chlormezanon, carisoprodol, eperisone, phenprobamide, etc. However, these drugs act on spinal cord interneurons to inhibit monosynapse and polysynapse, and thus, have side effects including central nervous system depression and muscle weakness.
U.S. Pat. No. 3,313,692 describes racemic carbamate compounds useful as central nervous system drugs with significantly decreased side effects. U.S. Pat. No. 2,884,444, U.S. Pat. No. 2,937,119, and U.S. Pat. No. 3,265,727 describe dicarbamate compounds useful as central nervous system drugs, and N-isopropyl-2-methyl-2-propyl-1,3-propandiol dicarbamate described in U.S. Pat. No. 2,937,119 was released on the market as a muscle relaxant under the product name of Soma. Muscle relaxants are used as an agent for improving symptoms including hernia of an intervertebral disk related to muscle spasm that is involved in skeletal muscle diseases, and vascular disorders of the spinal cord, spastic paralysis of the spinal cord, cervical spondylosis, cerebral palsy, sequelae of injuries (spinal cord injuries, head injuries), spinocerebellar degeneration, etc., and Muscle relaxants are also used as an adjuvant to anesthetic agents.
Throughout this application, various publications and patents are referred and citations are provided in parentheses. The disclosures of these publications and patents in their entities are hereby incorporated by references into this application in order to fully describe this invention and the state of the art to which this invention pertains.